virtio-console: Also throttle when less was written then requested

This is necessary so that we get properly woken up to write the rest.

This patch also changes the len argument to the have_data callback, to
avoid doing an unsigned signed comparison.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
index 50350303cd5cf9ed45b9d9598098f33120945213..061f4bd63622a029c8b65979ece21101057419e7 100644 (file)
--- a/hw/char/virtio-console.c
+++ b/hw/char/virtio-console.c
@@ -34,7 +34,8 @@ static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond,
 }
 
 /* Callback function that's called when the guest sends us data */
-static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
+static ssize_t flush_buf(VirtIOSerialPort *port,
+                         const uint8_t *buf, ssize_t len)
 {
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
     ssize_t ret;
@@ -47,7 +48,7 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
     ret = qemu_chr_fe_write(vcon->chr, buf, len);
     trace_virtio_console_flush_buf(port->id, len, ret);
 
-    if (ret <= 0) {
+    if (ret < len) {
         VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 
         /*
@@ -56,7 +57,8 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
          * we had a finer-grained message, like -EPIPE, we could close
          * this connection.
          */
-        ret = 0;
+        if (ret < 0)
+            ret = 0;
         if (!k->is_console) {
             virtio_serial_throttle_port(port, true);
             qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, chr_write_unblocked,

diff --git a/include/hw/virtio/virtio-serial.h b/include/hw/virtio/virtio-serial.h
index 7c71304d106a6d97daf0558d21cc38a3bc421400..1d2040b245b80cdf067def377d06561f0812c4e0 100644 (file)
--- a/include/hw/virtio/virtio-serial.h
+++ b/include/hw/virtio/virtio-serial.h
@@ -104,7 +104,7 @@ typedef struct VirtIOSerialPortClass {
      * 'len'.  In this case, throttling will be enabled for this port.
      */
     ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf,
-                         size_t len);
+                         ssize_t len);
 } VirtIOSerialPortClass;
 
 /*